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« Nanotechnology and the Singularity | Main | Power and Struggle »

April 23, 2005

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Philip Moriarty

From the New Atalantis article: "Nanotechnology is a "bottom-up approach much like building a sculpture atom by atom and molecule by molecule instead of cutting it from a larger rock," said a Republican Senator. They were describing an area of advanced nanotechnology called molecular manufacturing."

"Bottom-up" does not necessarily mean "molecular manufacturing". Many nanostructured systems are now constructed via a bottom-up rather than a top down approach (using self-assembly either close to- or far from equilibrium) that has nothing to do with the MNT strategy. Why is the author of the New Atlantis piece so certain that the senator in question was describing molecular manufacturing?

Philip


Mike Deering

I think that self-assembly and positional assembly will both be utilized in MM systems such as a nanofactory. Just as an automobile is a combination of chemical reactions, mechanical transfers, electrical processes, and magnetic components, and optical functions, so to will MM be composed of a variety of functionalities, each appropriate to their engineering purpose.

You're talking apples and oranges, and we're talking an entire produce economy.

Philip Moriarty

Mike,

If it's self-assembly than it's not MNT (or MM, if that's the currently preferred acronym). MNT **necessitates** computer-controlled atomic and molecular manipulation where every atom is in a pre-defined site. If the goal of computer-controlled atom-by-atom construction (of 'virtually any material' [Drexler, "Engines of Creation"]) is too difficult to achieve, then fine, admit defeat and use self-assembly as an alternative to build a structure from the bottom up. However, don't then pretend that the structure in question was constructed using the principles underlying MNT.

This is not just a matter of "apples and oranges". It's a question of not misleading the public as to the fundamental principles underlying MNT. "Bottom up" is not solely MNT. Self-assembly is not MNT. (It's not even a step on the way towards MNT if one reads Chapter 16 of "Nanosystems" - where are the external control instructions in self-assembly?).

Leaving aside the usual obfuscation and misappropriation that are now a cornerstone of the Drexlerian position, my point in the post above was the following: where is the evidence that there is a "discrepancy between what Congress expects and what federal funds in fact support". Who has stated that Congress expects current funding via the NNI to be focused on MNT?

Philip

Philip Moriarty

By the way Mike, regarding the following quote on your website: "Within a short time, everything that can be known, will be known, and anything that is possible within the laws of physics will be achievable", you might like to read Bob Laughlin's most recent book on emergence. (See http://www.softmachines.org/wordpress/index.php?p=104 for a concise overview by Richard Jones).

Philip

Mike Deering

Philip thanks for the book link. It looks like an interesting one. Can't wait to read it.

Nanofactories that use the nanoblock paradigm will use self assembly at some stages. Molecules will be positionally assembled atom by atom and placed in micro chambers where self assembly will produce the nanoblocks like viruses in a cell. Then the nanoblocks will be harvested by machanical means to be further positionally combined into products.

Chris Phoenix, CRN

Mike, that's one way to do nanofactories, but it's not the only one. For example, the molecules might be made by bulk chemistry, then imported from solution into a non-solvent environment, then attached by mechanically-guided chemistry to form blocks and other structures which are never re-solvated. In that case, the only self-assembly would be binding the feedstock molecules right at the beginning.

Chris

Philip Moriarty

Mike,

There's much in Laughlin's book that is extremely thought-provoking and - as Richard Jones points out - much that proponents of *any* flavour of nanotech might quibble with! ("Nanobaubles" is certainly an emotive term..!)

You state that "molecules will be positionally assembled atom by atom". As you know, this is the concept at the core of MNT. Without this - i.e. if self-assembly (perhaps directed by external fields) *alone* is used for construction - then the MNT 'vision' has not been brought to fruition. There is a vast amount of research on self-assembly of nanostructured systems - a vanishingly small amount of this - to the best of my knowledge, zero - was inspired by "Nanosystems".

We could debate back and forth for a very long time (as Chris and I have in the past: http://www.softmachines.org/wordpress/index.php?p=70) on the feasibility of molecular manufacturing. Fundamentally, however, the debate is pointless if it's not supported by experiment. My purpose in posting the comment above was not to re-open the debate but to point out that the "Nano Research Future" comment (based on the editorial in "The New Atlantis") is misleading as it suggests that "bottom up" nanotechnology only involves MNT.

Philip

Mike Deering

Well, you're right of course. We could argue this further without accomplishing anything. We have a different estimation of the rate of progress of technology and the difficulty of developing MM. I think the problem is the cultural divide between scientists and engineers. Scientists almost always overestimate the difficulty of developing technologies. The reason is that scientists are trained to work toward understanding something, while engineers are trained to work toward making something work. Understanding is a much more ambitious goal than making work. Scientists think you have to understand something before you can make it work. Engineers know that you don't have to have any idea how the underlying processes function, just a list of things the happen in certain circumstances. Engineers will mess around with the tools of nanotech and come up with MM before the scientists have figured out all the math. Of course, the best scientists are also good engineers, and the best engineers are also scientists. Some call them physics rock stars. Practical success is the most persuasive argument, and that is just a matter of time.

Philip Moriarty

Mike,

I reiterate the comment I've made to Chris in the past. It's now been 15 years since the publication of Eigler and Schweizer's seminal paper on atomic manipulation. Since then, there has not been a single demonstration in the lab. (by scientist or engineer) of even one step in a Drexler-type mechanosynthesis sequence. There is *no* experimental work towards the implementation of molecular manufacturing for covalently bound systems (such as diamond or silicon) as described by Drexler in "Nanosystems". (Current world-leading work on bio- and biomimetic systems is *not* a demonstration of molecular manufacturing. I would ask that those who suggest that it is re-read "Nanosystems").

"Engineers know that you don't have to have any idea how the underlying processes function, just a list of things the happen in certain circumstances."

I can't agree that it's simply a cultural difference between engineers and scientists. It's a question of feasibility. The statement that molecular manufacturing will be able to make "virtually anything" [Drexler, "Engines of Creation"] is fundamentally flawed. Only a very small subset of covalently bound solids are open to mechanosynthesis as laid out in "Nanosystems" (...Drexler made a very smart choice when choosing diamond). So, in this sense, Drexler's vision of a molecular manufacturing technology capable of making 'virtually anything' or being able to handle practically all the elements in the periodic table is already clearly bunk. (I'm guessing that the usual tired Drexlerite response to this will be that I'm raising a 'straw man' because - of course - 'virtually anything' doesn't actually mean 'virtually anything', just as 'universal assembler' apparently doesn't actually mean 'universal assembler': see comments under http://www.softmachines.org/wordpress/index.php?p=50)

Does this mean that developing a set of mechanosynthesis reactions for a well-chosen materials system (e.g. diamond) is impossible? No - just associated with incredible practical difficulties. One might imagine that those practicalities fall within the remit of an engineer to solve, but at the nanometre level the traditional boundaries between physicist, chemist, materials scientist, biologist, and engineer effectively collapse. This is what makes nanoscience so exciting - it represents a (natural) convergence of the scientific and engineering disciplines. One can look on the problem of implemetning the machine level steps of mechanosynthesis purely as an engineering problem but this is terribly misguided: the problem is essentially that of chemistry.

Nevertheless, and as I've also said in the past, give me a plausible proposal to implement mechanosynthesis steps on a covalently bound solid and I'll try to implement those steps. Freitas' strategy - which I discussed at length with Chris Phoenix - was an extremely important first step towards putting a proposal on the table that had the potential to be implemented in the lab. Key elements didn't hold up to scrutiny but at least Freitas had the courage and vision to put forward a concrete proposal. This makes a refreshing change to the misguided vision that it's possible to simple "abstract out" the most important element of the mechanosynthesis process - the chemistry.

As regards the misleading "New Atlantis" editorial which prompted our exchange of views, it's worthwhile reading what Richard Jones has to say on the matter: http://www.softmachines.org/wordpress/index.php?p=107

Best wishes,

Philip


Mike Deering

Philip, maybe I'm not in the mainstream of the MNT conspirators. I like the fact that research is going in all directions. It would be a mistake for all the NNI's millions to be exclusively directed at MNT. Let's fund Bio-nano, wet-nano, bulk-nano, nano dots, nano circuits, nanotubes, fullerene drug delivery systems, engineered viruses, gene therapy, nano-optics, nano-magnetics (is there such a thing?), along with the least ambitious first steps of MNT. So we put off the "universal" assembler, and the "virtually anything" for now, no big deal. Understanding that research dollars are a scarce commodity, even for the government, the consequences of failing to pursue MNT in the face of competition from unfriendly counties could be disastrous in the long run. It is our best interest not to leave this door closed.

Tom Craver

A point of fairness to Drexler - Engines of Creation was a general vision of atomic manipulation - not restricted to diamond or MNT as currently envisioned.

That he and others have since focused on a particular engineering approach to nanotechnology - diamond-based MNT - doesn't seem to invalidate the original claim.

If diamond (or other) MNT is achieved, further advances to manipulate other atoms should be possible, making it indeed possible to make "virtually anything" via nanotechnology.

Richard Jones

Tom, your point of fairness is very well taken. I've always tried very hard in my writing to distinguish between the general principles of nanotechnology outlined in Engines and the specific implementation of MNT discussed in Nanosystems. It's actually people like Chris who blur this distinction by insisting that all nano roads must lead to MNT.

Mike, I think you're qutie right to celebrate diversity. Basically we don't know which horse will win so it's worth backing as many as we can afford. We should also recognise that this diversity will lead to opportunities that are at the moment completely unexpected. There's one important point, though. Although it's tempting to think of the NNI as a project that's steered with great deliberation, the truth is that large parts of it consist of a bunch of administrators sitting around in DC waiting for people to send proposals in. If there's not enough effort going into things that might lead to MNT, that's because there aren't scientists who think that this direction is one that's worth pursuing. If MNT enthusiasts want more efforts put in the directions they think are worthwhile, then they're going to have to convince scientists that it's in their interests to write some proposals along these lines. CRN's current policy of gratuitously insulting any scientists who bother to talk to them doesn't seem a great way to go about this process.

Chris Phoenix, CRN

Mike (and Tom),

1) No one is proposing that the NNI should spend all its research dollars on MNT.

2) The phrase "universal assembler" has been misinterpreted from the beginning. If you read the relevant section of Engines Chapter 1, the phrase "depending on design" makes it clear that there was no single "universal" assembler, but rather a (potentially large) family of "enzyme-like second-generation machines" that could be designed to collectively do a wide range of desired reactions.

http://foresight.org/EOC/EOC_Chapter_1.html#section06of10

Chris

michael vassar

Since Bob Laughlin seems to basically reject the metaphysical foundations of science, it's not obvious to me that he adds anything to the debate. Surely no-one here thinks that biology is impossible or that it uses its own rules at odds with those of physics.

Richard Jones

The rules of biology aren't at odds with those of physics. It's more that (to be more specific) the laws of genetics are orthogonal to the laws of quantum field theory, in the sense that they are consistent with them, but not contained in them. He certainly rejects some naive but widely held views of what the foundations of science are, but his views, as my commentary pointed out, are actually pretty mainstream in terms of what philosophers of science think. What has he got to add to the debate? I hesitate to comment here, since the silicon 7X7 reconstruction is one of his favourite examples.

Philip Moriarty

Chris,

Re. universal assemblers, from "Engines of Creation":

"....enzyme-like second-generation machines will be able to use as "tools" almost any of the reactive molecules used by chemists - but they will wield them with the precision of programmed machines. They will be able to bond atoms together in virtually any stable pattern, adding a few at a time to the surface of a workpiece until a complex structure is complete. Think of such nanomachines as assemblers. "

The issue is not that there'll be a single assembler capable of carrying out all reactions. I fully understand that Drexler did not suggest this. (I have pointed this out in the past to you, Chris, and resent the continual implication that I'm 'misinterpreting' what Drexler wrote. The passage from "Engines of Creation" above is clearly written and very difficult to misinterpret.). What Drexler argues is that a *family* of assemblers will be able to carry out mechanosynthesis reactions "using almost any of the reactive molecules used by chemists" and to "bond atoms together in virtually any stable pattern". Given the constraints on the parameter space of the mechanosynthesis 'machine language' we've discussed at length before, Drexler's vision that a family of assemblers will be able to build 'virtually anything' is, as stated in a previous post, clearly bunk.

Tom states: "If diamond (or other) MNT is achieved, further advances to manipulate other atoms should be possible, making it indeed possible to make "virtually anything" via nanotechnology".

I'm afraid that I simply can't agree and have made detailed arguments before (see http://www.softmachines.org/wordpress/index.php?p=70) as to why the idea that molecular manufacturing will be able to make "virtually anything" is wholly misguided. I am not going to repeat those arguments here. Instead, I'll simply quote from a letter I sent to Eric Drexler some time ago (for more information please follow the link above):

“So, far from delivering the ability to synthesise ‘most arrangements of atoms that are consistent
with physical law’ or to manufacture “almost any… product ….that is consistent with physical and
chemical law”, an extremely judicious choice of materials system, possible intermediate/ transition
states, diffusion barriers, and symmetry is required to attempt even the initial, most basic and
faltering steps in molecular manufacturing. “

Just because one can attempt mechanosynthesis with diamond **does not** mean that the process is then universal (via either a single assembler *or* a collection of assemblers) for any choice of element or material. Drexler chose hydrogen-passivated diamond for extremely good physical and chemical reasons. His argument in "Engines of Creation" that molecular manufacturing via mechanosynthesis is applicable to virtually any material using 'almost any of the reactive molecules used by chemists' is not supported by any type of analysis. Indeed, the very many careful considerations (laid out in "Nanosystems") that led Drexler to choose H-passivated diamond clearly show that the mechanosynthesis strategy can not be directly 'portable' from materials system to materials system.

Philip

Mike Deering

These questions of "universal assemblers" building "virtually anything" is a second or third stage matter, whose immediate importance may be overshadowed by the fact that the first stage diamond mechanosynthesis under computer control will completely change the world.

Philip Moriarty

Mike,

Can't agree, I'm afraid. Mechanosynthesis under computer control can either build 'virtually anything' - as repeatedly put forward by Drexler - or it can't. Proponents of Drexler's work continually raise the spectre of the 'straw man' when they believe that Drexler's work has been misinterpreted. "Virtually anything" is not synonymous with "diamond" - this is not a 'straw man' or a misinterpretation and it's certainly not a "second or third stage" matter: if molecular manufacturing is capable of constructing only an extremely narrow subset of materials then this is an entirely different proposition from that laid out in "Engines of Creation". (Drexler has told me in the past that the analysis in "Nanosystems" entirely supports the scenarios put forward in "Engines of Creation" - I see absolutely no evidence for this).

Richard Jones states above: "If MNT enthusiasts want more efforts put in the directions they think are worthwhile, then they're going to have to convince scientists that it's in their interests to write some proposals along these lines". I've stated before (on a number of occasions) that as an experimental physicist, if a proponent of Drexler's 'vision' puts forward a plausible strategy for the development of diamond mechanosynthesis - **that stands up to intense scrutiny via peer review ** - then I am willing to try to implement that proposal. The idea that MNT has been 'locked out' of the NNI is simply ludicrous. There is no experimental programme on the development of diamond mechanosynthesis because a single, coherent strategy (as required for a scientific proposal) to develop this technology has not been put forward by the research community.

I'll ask a (now rhetorical) question I've asked of Chris before: just why does such a very small percentage (~ 0%) of the MNT community comprise scientists (physicists, chemists) who could actually attempt an experiment to implement diamondoid mechanosynthesis? Does this not speak volumes?

Best wishes,

Philip

michael vassar

I believe Chris has answered your point on the number of physicists in the MNT community, (main point, MNT in Engineering, not physics.) all that I have to add is that the fraction of physicists and chemists in the population is not very large at any level of intelligence. The US produces less than 800 physicists per year!
At any rate, it is far from obvious that Nanosystems leads rapidly to Engines. Nanosystems obviously *supports* Engines, in showing that some of the radical goals from Engines are practical and not overwhelmingly complex, and in providing tools which should make others substantially easier.
Even assuming that Engines is not a short term consequence of Nanosystems, I remain baffled by your appearent belief that Nanosystems is not utterly world-changing. It seems utterly clear that the technology described there would be much a more promising approach to achieving Engines type goals than the vast majority of well funded nanotechnology research projects which assert long term goals that are basically taken from Engines.

Tom Craver

Imagine someone at the opening of the industrial era commenting on the idea of using machines to make goods, and criticizing the idea of a machine that can shape high precision parts out of steel.

"Industrial machines can either produce 'virtually anything' or they can't. 'Virtually anything' is not steel parts."

I can understand criticizing MNT in general - but if MNT could be made to work for diamond, why do you think that it could not be extended - with substantial effort no doubt - to work with elements other than carbon and and forms other than crystalline?

Philip Moriarty

Michael,

Treating MNT as solely an engineering discipline is simply wrong. Any attempt to develop MNT will necessitate - like any nanoscale science research effort - highly cross-disciplinary work involving physicists, chemists, biologists, and engineers. The 'machine language' of mechanosynthesis is based on fundamental chemistry - not engineering.

You also entirely miss the point re. experimental physicists' and chemists' 'input' to MNT. I suggest that you visit the websites of any of the following scientific journals: Science, Nature, Physical Review Letters and Physical Review, Nano Letters, J. Phys. Chem (and many more I won't list here). Consider the huge volume of experimental nanoscience-related work published in these journals every week/month. How much of that work is related to the development of MNT as outlined in "Nanosystems"? I would guess that the number is extremely close to zero. Why? Because to the best of my knowledge not one research group in the world (and there are **very many** research groups active in nanoscience - in the EU alone the 6th Framework Proposal has allocated ~ €1.3 billion for nanoscience-related research) has put forward a proposal to implement MNT in the lab.

"It seems utterly clear that the technology described there would be much a more promising approach to achieving Engines type goals than the vast majority of well funded nanotechnology research projects which assert long term goals that are basically taken from Engines."

"Well-funded nanotechnology research projects which assert long term goals that are basically taken from Engines"? Please point me to the appropriate references/ URLs.

"I remain baffled by your appearent belief
that Nanosystems is not utterly world-changing."

**If** "Nanosystems" is viable then, of course, the technology will be revolutionary - I wouldn't argue otherwise. However, the viability of even the simplest mechanosynthesis reaction (hydrogen abstraction) has not been demonstrated (depsite the availability of tools that should in principle enable this reaction). Don't you think it's a little premature to accept that the molecular manufacturing concept outlined in "Nanosystems" is a 'given'?

Tom states: "...but if MNT could be made to work for diamond, why do you think that it could not be extended - with substantial effort no doubt - to work with elements other than carbon and and forms other than crystalline"

Tom, I'm afraid that I haven't got time to repeat the detailed arguments re. surface reconstruction, diffusion barriers, transition states, and fundamental chemistry that I've covered with Chris in the past ( http://www.softmachines.org/wordpress/index.php?p=70). In 'brief': I'm not stating that it's impossible to attempt mechanosynthesis with a (well-chosen) element other than carbon. My argument is that the constraints imposed by mechanosynthesis narrow the available parameter space so that only a very small subset of materials is viable. Note that this is not simply my opinion - it is in **full agreement** with Drexler's work in "Nanosystems", Merkle et al.'s assertions in the early nineties (and his rebuttal to the "Waiting for Breakthroughs" Sci. Am. issue almost ten years ago), and a number of Chris Phoenix's statements on this blog.

Chris has stated, for example, that if a surface reconstructs, then that surface won't be used for mechanosynthesis. The problem is that only an *extremely small* subset of surfaces don't reconstruct. GaAs(110), for example, relaxes but doesn't reconstruct; H:Si(111) and H:C(111) use hydrogen to 'mop up' dangling bonds and thus reduce the free energy so that reconstruction is not 'required'. There are a few other unreconstructed surfaces but their number is tiny compared to the family of surfaces that *do* reconstruct. Let me list a few reconstructed surfaces off the top of my head: Si(111)-(2x1), (7x7); Si(100)-(2x1); C(100)-(2x1); GaAs(111)A-(2x2); GaAs(111)B-(2x2) and (Rt19 x Rt 19)R23.4 degrees; GaAs(100) - (...deep breath...) c(4x4), (2x4), (1x6), (2x6), c(2x8), c(8x2), (4x2)). And these are just the clean surfaces: further extensive families of reconstructions are induced when other elements are added to the clean surface (metals on Si(111), for example, tend to induce (Rt 3 x Rt 3)R30 reconstructions but there are many, many exceptions for Si(111) (and let's not start on Si(100) and Si(110)).

Merkle has stated that mechanosynthesis strategies will avoid structures with "too many" dangling bonds. Drexler himself - and this is the key point - chose H-passivated diamond precisely to avoid problems with surface reconstruction, diffusion, and reactivity. I'm not asking that you accept my word on the importance of a judicious choice of material: read "Nanosystems" or Merkle's rebuttal of the Sci. Am. "Waiting for Breakthroughs" issue (at the foresight.org website) - these key proponents of MNT clearly realise that there are strong fundamental constraints on the choice of material.

...but we're not getting anywhere are we? Time and time again, detailed scientific arguments regarding the viability of mechanosynthesis are put forward and ignored. It's clear that proponents of MNT are happy to wholly accept the 'validity' of "Nanosystems" without any attempt at experimental verification: this is anathema to me.

Best wishes,

Philip

todd

I would just like to comment on the above blog. In reference to the fact that there is not a specific design for a molecular manufacturing device currently available. After all if there was any design available today we would simply build it the mere fact that there is not a design does not preclude or in any way discourage the progress that is being made. Although I do not perhaps have the number of years and relative wisdom under my belt. I do believe and please correct me if I'm mistaken that one the Manhattan Project began there was no clear and specific design for a nuclear weapon. When the space shuttle was built that was not a clear and specific design for the vehicle. To say that the likely manufacturing device is less complex or more complex than either these two projects would be speculative it is nonetheless extremely complex. I would think at this point a prudent step would be to put together a team made up of a few hundred individuals willing to commit to five to ten years project. The group will need to be funded in the billions to start and should investigate every possible road or path that leads to the eventual goal off a self replicating device capable of producing useful products. This is clear and if I were in a position of power or great wealth I would consider it an honor to begin such a project and indeed a responsibility to all mankind to see this done.

Todd

Philip Moriarty

"I would think at this point a prudent step would be to put together a team made up of a few hundred individuals willing to commit to five to ten years project. The group will need to be funded in the billions to start and should investigate every possible road or path that leads to the eventual goal off a self replicating device capable of producing useful products"

Todd, good luck in convincing research councils and governments across the world to invest 'billions' in a technology where not even the most fundamental 'proof of principle' experiment (e.g. demonstration of a hydrogen abstraction tool) has been implemented! I've suggested in my debate with Chris (see link in my previous post) a possible 7 step sequence as a 'proof of principle' experiment. An experimental programme dedicated to attempting this - or an equivalent mechanosyhtnesis sequence - would go a long way towards convincing the research community to invest time and effort in MNT-related science.

Best wishes,

Philip

todd

As an sure everyone here knows I am not a chemist nor my physicist nor in my mathematician in fact I'm a very small and insignificant person. However I am a self replicating (with a little help) device, capable of building useful products. As I and here the concept for the above discussion is defined in the answer. And the answer to the question is yes it is possible to construct a self replicating device capable of producing useful products. This device could use any one of the hundred different elements utilizing any one of the hundred different chemical reactions following alliance of any one of a hundred different paths to the eventual goal of completion.

We do not have to find every single chemical reaction that produces a carbon are otherwise based molecular manufacturing device we only need to find one chemical reaction that produces such a device. And as my esteemed colleague above has stated there are several possible chemical reactions that could fulfill the requirements for molecular manufacturing. And I certainly will not dispute his findings here. In the past we have discussed the possibility that a mere five or six reactions would be sufficient for self replication. Of these five or six I would think there are good candidates for each.

One thing I would say is perhaps in support of my above colleague comments we are simply too early in the curve and the complexity is too great for the completion of the device. Given another two or three years things may change where individuals and power can be convinced that the project should be undertaken and that the perceived goals are within reach in a timely manner. I do not necessarily agree with the above statement I just made but it is nonetheless a possibility.

todd

Philip Moriarty

Hi Todd,

"However I am a self replicating (with a little help) device, capable of building useful products"

Richard Jones' "Soft Machines" book covers the biological approach to nanomachines in great depth - I think that you might enjoy reading it. (Visit: http://www.softmachines.org/index.html for details).

Best wishes,

Philip

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